1. Field of the Invention
The present invention relates to a blood flow measuring apparatus in which a blood stream flow velocity in organs of a human body, especially the heart, is visualized and is displayed with an ultrasonic wave image of an organ. The hemodrometer being particularly effective in carrying out a rapid and correct diagnosis of heart disease.
2. Description of the Related Art
An ultrasonic wave is transmitted into a human body and a reflected wave is received and displayed on a Braun tube, thereby obtaining an image of a particular organ of the human body. Such an apparatus (i.e., an ultrasonic wave diagnosis apparatus) is widely used in the diagnosis and treatment of diseases in the human body. When the ultrasonic wave is impinged onto a moving target such as the blood and is reflected therefrom, deviation of a frequency of the reflected ultrasonic wave by a Doppler signal causes a deviation in the value corresponding to the blood stream flow velocity from a transmitting frequency. A blood stream flow velocity (i.e., a flow velocity component in the sending and receiving directions of the ultrasonic wave) can be obtained by the above deviation, and the blood stream flow velocity distribution can be displayed on the Braun tube. When a disease affecting, for example, the valves of the heart, is present, the blood stream in the heart is in an abnormal state, and therefore, a disease of the heart can be correctly and easily diagnosed by observing the blood stream flow velocity distribution diagram displayed on the Braun tube.
A one-dimensional blood stream flow rate distribution display, such as a blood stream flow velocity distribution on a specified line, is displayed as an M mode image having a time axis, and a two-dimensional blood stream flow velocity distribution display such as a blood stream flow velocity in an organ is displayed as a B mode image.
In the one-dimensional blood stream flow velocity distribution display, the blood stream flow velocity is displayed as a variation in brightness or as a color modulation, or as a graph. In the two-dimensional blood stream flow velocity distribution display, the blood stream flow velocity is displayed as a variation in brightness or as a color modulation.
In the one-dimensional blood stream flow velocity distribution display, when the blood stream flow velocity is displayed as a brightness variation or as a color modulation, the blood stream flow velocity itself can be measured with a high accuracy, however, the brightness variation or color modulation cannot be read with a high accuracy, and it is difficult to determine the spatial position of the organ being measured. When the blood stream flow velocity is graphically displayed in the one-dimensional blood stream flow velocity distribution display, the blood stream flow velocity can be read with a high accuracy, however, it is difficult to determine the position of the organ being measured.
In the two-dimensional blood stream flow velocity distribution display, it is easy to determine the position of the organ being measured but the measurement accuracy is low, and if an increase in the measurement accuracy is desired, one scanning line must be transmitted and received many times, which increases the time necessary to obtain one complete picture.